Grinding machine



Nov. 2, 1937. R. A. COLE 2,097,783

GRINDING vMAGHINE Filed Oct. 9, 1935 2 Sheets-Sheet 200|000000000OOOCOOOOOIOIIOOOI HYMU/vu A. Em E /W 40% @M .WQWAFW' GnomwuPatented Nov. 2, 1937 UNITED STATES l onnvnmo Maclmvr: o, Ramond A.Cole,.Worceatei-,' Mass., assignor to Norton Company, Worcester,

Mass., a corporation of Massachusetts Application October. 9, 1935,Serial No. 44,204

4Clnims.

The invention relates to grinding machines and with regard to its morespecific features to a sizing mechanism therefor.

One object of the invention is to provide an electric sizing device ofsimple construction and dependable in operation. Another object of theinvention is to provide 'a sizing device having no contact with a workpiece. Another object of the-invention is to provide an' electric sizingdevice whose sensitivity is not affected by aroing. Other objects willbe\in part obvious or in part pointed out hereinafter. A

The invention accordingly consists in the features of construction,"combinations of elements, and arrangements of parts as will beexemplied in the structure to be hereinafter described and the scope ofthe application of-.which will be indicated in the following claims. v

Inthe accompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of my invention;

Fig. l is a vertical transverse sectional view.'

showing the hydraulic actuating and control mechanism for the cross feedslide of a grinding machine, and illustrating also the caliperingmechanism,

Fig. 2 is a fragmentary vertical sectional view, the section being takenon the line 2-2 of Fig. l, 1 Fig. 3 is-`an electrical and opticaldiagram.

I provide a grinding machine including a. Y machine base i6 havingtheo'usual ways Ii, i2 for the support of a work table I3 upon which issupported a headstock and a tailstock, not shown, for the support androtation of a workpiece I4 which 'is to be` exteriorly ground. 'I'heusual mechanism foi' traversing the work piece by longitudinalreciprocation may be provided, but

,so' far as certain features of the invention are concerned thegrindingmay be by the so-called ,plunge-cut" method, in which the grinding wheeladvances relative to the work piece without relative traverse thereof,or with only limited re ciprocation for the removal of grinding lines.

Mounted on the usual-cross feed slideway, not shown, is a cross slide-I5 of any usual or desired form having a wheel head I6 which journalsin journals i1 the'spindle i3 of a 'grinding wheel i3. The wheel I3 mayhave a wheel guard 20 of any usual or desired construction.

Referring now to Figs. 2 and 3,'fastened to the inside of the machinebase I6 underneath theA tableV i3 are a pair of brackets 2|, 2|supporting journals 22, 22 for a `rock shaft 23 upon which is mountedoptical apparatus generally indicated by the numeral 24. 'Ihis opticalapparatus 36 and top plate 3l, the plates 21, 30 and 3| being integralwith each other and with the ,web 28. Extending downwardly from thebottom of `the box 2.6 and integral therewith is a web 32having ajournal 33 integral therewith, through 10 which journal 33V passes therock shaft 23. 'I hus the optical apparatus 24 is supported yby themachine base, and it maybe adjusted in position parallel to the ways il,and i 2 and by moving the journal33 along the shaft 23, and `when a l5desired position of adjustment is attained the journal 33 is locked uponthe rock shaft 23 as by means of a set screw 34, there being a hole 35in the machine frame for Aaccess to the optical apparatus. In so much asthe shaft 23 may always turn in the `journals 22, the optical apparatus24 may be swung back and forth and adjusted angularly'around the axis ofthe shaft 23. Extending downwardly from theK journal 33 and preferablytegral therewith is an arm 36 4which is connec ed by means of a .spring39 to the machine base i6, the spring 39 serving to urge the entireoptical apparatus 24 in a clockwise direction, Fig. 1. A screw 40 havinga hand wheel 4i for convenient adjustment from 0 the front of themachine constitutes an adjustable stop for the arm 38,' by means ofwhich the position ofv the optical apparatus may be delicately adjusted.For quick forward movement of the optical apparatus, however, it may be35 swung to the front of the machine by hand, and to hold it' therewhile changing *work pieces any desired latch or the like may beprovided, such as the' hook 42 andeye 43.

In the box 26 I provide` a pair of electric light to` bulbs `4t -which`may be ofthe point of light type or of the ribbon filament type in orderto produce a beam having as little stray ,li ht as possible withinpractical limits. In the box-26 is also a mirror 46- set at anangleapproxi- 45 mately to the axes of the p i tubes 25.

In each tube 25 is a pair of 'con a n "lenses 41,

,48, and in plate 21l located/inl oriil ,es 43 are concave lenses 50.`The f r 46, lenses 41 `and 48, and lenses 50 may be made adjustableinjthe 50 usual way, not herein vshown in detail as constructions forlens adjustments and the like are well understood. Attached to the web26 and extending from' it on either side is a pair ofsup4 ports 5I forconvex lenses 52. Extending for- '55 wardly from the plate 30 andsuitably insulated yare thecdnventional four-hole sockets 53 for thesupport of photoelectric cells 54 (only two of the .prongs beingelectrically connected).

. the filaments of the lights 45, are reflected by the a hand wheel 68.v The brackets 2|have slots 69' mirror'46 through the two pairs ofcondensing lenses 41 and 48, and the converging beams are spread to someextent by the lenses 50. However, between the lenses 50 and 52 I desirethat the beams shall become crossing beams 51 and 58 with foci F in thehorizontal plane of. the axis of the work piece I4. From the foci F thebeams spread and are by the lenses 52 transformed into crossing beams 59and 60 whose cross sectional 'area is approximately equal to that of thecathodes 6| of the photoelectric cells 54 at that point.

The axes of the beams 55, 51 and 59 are. parallel to each other and tothe axes of the beams 56, 58 and 60. But I desire that the work piece I4shall uncover them successively. The interval between uncovering of thetwo beams is a matter of a few ten-thousandths of an inch, for examplefteen ten-thousandths of an inch (.0015"), and this may be achieved inmany ways. For example, and referring to the lower part of Fig. 2, theleft-hand bracket 2| may have a portion 65 depending therefrom whichincludes a boss 66 through which passes a screw 61 controlled by and areheld to the frame I by bolts 10 passing through the slots 69, and byreason of the direction of elongation of the slot 69 the brackets may beadjusted in a horizontal direction, and preferably the shaft 23 is ashouldered shaft so that all play can be taken out of the parts whenvthe brackets 2| are austed and fastened in position. 'I'he left-handend of the shaft 23 may be moved to'the front of the machine by anamount suicient to make the difference, in ten-thousandths of an inch,between uncovering of the beams 51 and 58, by turning the hand wheel 68,which will spring the left-hand bracket 2| outwardly to a slight extent,or if this is not enough the lower bolts` may be slightly loosened.

Various expedients may beadopted to form a very narrow focus F for eachbeam. With the system of lenses shown and described, if the filament ofeach bulb 45 were a geometrical point the foci F would also begeometrical points except for color aberration. But a color lter may beused in connection with theapparatus for more accurate results, and thiscolor iilter may be placed under the lowermost lenses 41. .The focus Fof 'each beam,`however, is still an image of the lamp lament.Point-of-light electric bulbs are now available, in which the luminouspart is very small. I lprefer to use such, but a ribbon filament lighthas 4a relatively small light source. However, the use of diaphragms,while they *diminish the intensity of the light, maybe resorted to. Afeature.of the electrical apparatus about to be described is that, inconjunc-A tion with a photoelectric cell, it is quite sensitive andresponds to a certain quantum of light, which while not absolute in thetrue sense is nevertheless unvarying within practical limits of a fewten-thousandths of an inch in the size of the work piece, when used inconnection with the apparatus of the invention.

In the preferred embodiment of the invention actuation of onephotoelectric cell 54 causes crossl pressure fluid is moving feedmovement between grinding wheel l0 and` work piece I4 to cease, whileactuation of the other photoelectric cell 54 causes the cross slide I5to retreat carrying the grinding wheel I0 dednitely away from the workpiece. Grinding between the first indication or electrical actuation andthe final coming to size takes place owing to the pressures set up inthe machine parts and such grinding, already known in connection withmanually operated. machines, has been termed sparking out. The inventionis shown embodied in an external cylindrical grinding machine, and thefirst actuation in some cases may be a slowing down of the cross feedrather than an actual discontinuance of ail movement. The mechanism ofthe present invention may be adjusted so as-to bring the cross slide I5to a stop at the first photoelectric actuation, or it may be adjusted soas to decrease the rate of cross feed rather than to stop it altogether.v

In the preferred embodiment of the invention I use av hydraulic crossfeeding mechanism which may be readily controlled by solenoids actuatedby the photoelectric cells 54. Referring again to Fig. 1', dependingfrom the cross slide I5 is a bracket |05 to which is attached a pistonrod |06 having a piston |01 located in a cylinder |08. A slide valve |09has reduced diameter portions ||0, III and ||2, which are separated byfull diameter portions fitting a valve bore H3. A port ||4 connects tothe right-hand side of the cylinder |08 while a port ||5 connects to theleft-hand side thereof. A passage ||6 connects the port ||4 with a valveport ||6, and a passage ||1 connects the port ||5 with the valve portH9. As shown in Fig. l, the ports ||6 and I9 are symmetrically locatedin the bore |I3, one being slightly to the right of the center portionthereof, and the other an equal distance to the left.

The bore ||3`also has ports |20, |2| and |22,

ythe former being a duid entrance port and con- `The valve |24 isconnected by piping |26 to the piping |25 as clearly illustrated.

The slide valve |00 may be operated manually by means of a rod having ahandle |3| -within convenient reach of the operator, and the slide valve|09 may be operated in one direction by means of a solenoid |32, asintegrally formed with the slide valve |06 is a rod-like portion |33 jwhich constitutes 'the core of the solenoid |02.

With the slide valve in the position shown in full lines in Fig. 1,'flnid underpressureis admitted from the piping |23 through the' port|2| and past the reduced portion to the port ||8 and the iiuid passesthrough passage ||6 to the port ||4 which is. at the right-hand end ofthe cylinder |05 and therefore the fluid will urge the piston |01 totheleft thus to move the cross slide |2 and carry the grinding wheel |5towards and to reduce the diameter of the work piece The parts are shownat the commencement of this operation in Fig. 1. While the piston |01 tothe left, nuid 1s being exhausted from the left-hand i0 side of thecylinder |08 and it flows `outwardly by way of port II5, passage II1,and port II! past reduced diameter portion ||2 and through piping |28 tovalve |24 and thence by way of pipe m imcpipe |25 which connects withthe l5 "23,037,783 fluid' sump or source of supply. When the valve I I9and by passage ||1 to p( [H6 and thus into thev mrt-hand side of the! 'cvunder los. This causes movement of the piston |01 to the right thuscarrying the grinding wheel I6 away from the work piece, and the fluidis forced out of the right-hand sideA of the cylinder |08, through portII4, passage. ||6, through port |-|3, past reduced diameter portion ||0to port |22 and by way of piping |25 to the sump.

It will be noted 4from the foregoingdescription that when the grindingwheel is traveling inwardly or to the left the exhaust fluid is passingthrough the valve |24, but whenthe grinding wheel is moving outwardly orto the right the exhaust fluid does not pass through the valve |24. Thevalve |24 is an adjustable metering valve and may be set to stopposition; thus it controls the advance of the grinding wheel andprocures a slow feed thereof and it is capable of being moved to -aposition to reduce thel feed or to stop it altogether. N

Considering now the construction of the valve |24 and referring to Fig.1, the pipe |23 connects to a port which opens into the side of acylinder |36. Opposite the port |36 is a port |31 connecting with thepipe |23. A -close tting piston |33 is located in the bore of thecylinder |33 and its movement to the left ls controlled by an adjustablestop screw |39. Connected to the'piston |33 by means. of a rod portionis another piston member |4|. Another 'rod |42 passes into a solenoid|43 and constitutes the core thereof. A spring |44 surrounds the corerod |42 and urges the piston |4| and therefore the other parts includingthe piston |33to the left. The rod |42 is connected at |45 to a brass or/other non-magnetic rod |46 which is in position" to be engaged by astop screw |41.

las

By properly setting the stop screw |39 as by means of a hand wheel |40the normal condition of the valve |24 may be determined. By setting Ithe stop screw |41 as by meansv of the hand wheel justed for such partof the cycle as involves |49 the condition of the valve |24 may be adtheenergization of the solenoid |43.

According to the preferred embodiment of the present invention themachine has three main parts to a cycle of operation. `There is first`the infeed of the grinding wheel when the solenoia |43 is deene'rgizedand the valve m 1s at its adjusted open or" widest open position. Thenfollows the grinding cycle while the solenoid |43 is energized, the'piston |33 being to the right and either restricting, the flow of fluidthrough the valve 24 more than previously or else cutting itoifaltogether. Thirdly, there is the return of the grinding wheel to aretracted position which is not controlled by the valve |24'at all.

-' The change from the first to the second phase of the grinding cycleis determined by one indi- .cation from the sizing apparatus and thechange. from the second to the third phase of the cycle is determined bya second indication of the sizing apparatus. Asso far described therighthand -photoelectric cell 54 (Fig. 2). sets in motion the changefrom the first to the second phase and the left-hand photoelectric cell34 sets in motion the change from the second to the third phase.Thenchange from the hthird to the rst phase might be edected in anymanner but so the solenoids and the operator has ample time to shift therod |33.

It should be noted that "either of the photolelectric .cells 54 'maybe-selected forinitiating either change, as this is simply a matter ofconnection of two pairs of final circuit wires. Furthermore, the sizingapparatus may be adjusted so that the change from therst phasmto the.

second phase occurs at the end of the movement which brings the grindingwheel against the work piece, or the change may beeifected when the workpiece is nearly to' size so that the'nal cuts will be in the nature o fa ne grinding operation. I prefer to adjust the valve |24 so that noadvance of the grinding wheel will take place after thesolenoid |43 isenergized, the further reduction of the work piece" being due to thestrain or spring in the machine parts and the nal cuts being what havebeen described yas dying out cuts, or simply sparking out. The

true cylindrical ne-nish and -accurate work.

'I'he calipering mechanism of the invention may l be readily adjusted sothatV the difference between actuations of the two photoelectric cellsis within the range of the amount of size reduction effected by adying-out cut.

Referring now to Fig. 3, the right-hand photoelectric cell 34 isassociated with amplifying and relay apparatus to energize the .solenoid|43, while the left-hand photoelectric cell 54 is associated withidentical apparatus to energize the solenoid |32. v Any` amplifyingand/or relayrapparatus 'may be used,` and direct or alternating currentmay be employed in any of the circuits, f

as my invention is not confined to any particular electricalarrangement. For Dill'pvses of illustration, however, I have disclosedin Fig. 3 a set ofcircuits which may be employed. f

Referring now to Figs. 3, a volt A. C. line |63 has connected to itconductors |53 and |51 leading to theterminals |53 and |59 ofa'transformi-zi` primary |30. Similarly conductors |5611 and I31aconnect to terminals |53a and 59a of a transformer primary I30a. Threesecondary coils |3I, |32 and |33 are energized by the primary coil |60and similarly secondary coils |6|a, |62a and |33a are energized by theprimary coil |30a. Non-inductive potentiometer -resistances |64 and |34aare connected across the conductors |33 and |33 and |65a and |66arespectively 0f the coils |3| Aand I6|a. Conductor |65 leads 'l to theanode |31 of the photoelectric cell 54 and conductor |3311 leads to theanode |61a of the photoelectric cell 54. Conductors |66 and |66a lead tocondensers |33 and |63a which are conenergize filaments |13 and I13a ofamplifying 0r triode tubes |14 and|14a. Grids |16 and I15a of the tubes|14 and |14a are connected by conductors |13 and |13a to non-inductiveresisters |11 and ma the other ends or which are connected to theconductors |10 and |10a respectively. Plates |30 and |30a in the tubes|14 and |14a respectivelyl are connected to conductors |3| and |3Iawhich conductors are connected to vterminals lland 32a. 'Ihe secductors|86 and ,|86a connect respectively to the.

movable elements |81 and |81a of potentiometers |64 and |64a andconductors |86 and |86a are also connected by leads |88 and |88a to themidpoints of coils |62 and |62a. It will now be seen that a certaindegree of illumination of right-hand photoelectric cell 54 causesenergization of relay coil |85, while a certain degree of illuminationof left-hand photoelectric cell 54 causes energization of relay coil|85a. The appa- In so much as the energzation of the relays |85 and|8511 may be momentary I further have provided a relay to close and keepclosed the final circuits upon any cnergization whatsoever of thesensitive relays. As shown in Fig. 3, conductor |56 also connects to aterminal |90 and conductor |56a connects to a terminal |90a. Conductor|51 connects to a relay c oil |9| and conductor |51a connects to a relaycoil |9|a. The other ends of the relay coils |9| and |9|a are con--nected to terminals |92 and |92a respectively.

Pendulum contactors |93 and |93a are adapted to connect terminals |90|92on the one hand and |90a|92a on the other hand. These pendulumcontactors are arranged to be operated by long arms |84 and |94a ofarmatures |95 A and |95a actuated by the coils |85 and |85a.

Energization of the relay coils |9| andy |9|a respectively, evenmomentary energization thereof, causes the closing of knife switches |91and |91a. These are double knife switches and one set of terminalsthereof is connected by shunt leads to the 1l0'volt A. C. wires |56, |51and |56a, |51a, respectively, while the other terminals of these knife'switches |91 and |91a connect to lines 200 and 200a which respectivelylead to the solenoids |43 and |32.

The pendulum contactors |93 and |93a may be of spring steel so thatnormally they lie in the position shown in Fig. 3 but a slight forcewill throw them into contacting position. The photoelectric cellcathodes 6| and 6| are preferably sensitive caesium plated cathodes anda certain definite amount of light on either of them will cause enoughcurrent to flow in either of the relay coils |85 and |85a to close thecir cuitby contactor |93 and |93a. By producing Anarrow beams of light51 and 58 and providing sensitive double relay apparatus one element ofwhich is a current measuring relay, I am enabled accurately to size thework.

In order to set up the machine, a work piece I4 ground to the desiredsize by 'means of hand gauges is placed in the machine centers and theoptical apparatus 24 is then moved towards the work piece to the fullline position shown in Fig. 1. In this iigure the apparatus is shownmoved to the right as far as itwill go and the smallest size of workpiece |4 -which can be gauged by a particular sizing apparatus accordingto the invention will 'cut oil' the beams of light. Both lamps 45 arelighted and the switches are closed. The hand; wheel 4| should now beturned to the right and first the solenoid |43 will actuate and laterthe solenoid |32. As the solenoid |32 actuates the adjustment is'nished.At this time the hydraulic motor is not operat- -lng at all.

'A scale may be provided in connection with the hand wheel 68 and if theinterval between actuations of the solenoids was not satisfactory, thehand wheel 68 may be turned and the trial gauging repeated. After thisis done the trial work piece I4 is removed, and an oversizedwork piece.is placed between the centers, and' the switches again closed and therod |30. is drawn toward the front of the machine. Many other manners ofadjusting the machine and many varied cycles of operation may beadopted.

In this embodiment of the invention the optical apparatus 24 is shownattached to the machine base and it extends through a slot 20| in thetable I3. This locates the sizing apparatus always opposite the grindingwheel. The slot 20| may be as long as the stroke of relative traversebetween the wheel and the work piece.

In order to eliminate a light intercepting lm of water upon the workpiece I provide a wiper 202 which may be made of rubber or nbre or anyother substance that will conform to the work pieceand remove the majorpart of any water or other matter adhering thereto. It will be observedthat the sizing apparatus of this invention leaves no scratch marks uponthe work piece and may be quickly adjusted for different sizes of workpieces.

It will thus be seen that there has been provided by this invention anapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asvarious possible embodiments might be made of the mechanical features ofthe above invention and as many changes might be made in the embodimentabove -set forth, it is to be understood that all matterv l. In anexternal cylindrical grinding machina,

means kfor holding and rotating a work piece to be ground, a grindingwheel, means for procuring a cutting advance between said means and saidgrinding. wheel, a support for optical apparatus including a long tube,lenses in the tube, a light source at one end of the tube, aphotoelectric cell xed with relation to the support and located withrespect to the light source and the lenses so that it. willconditionally receive light from the source via the lenses, means foraltering the cutting advance of the work piece, and amplifying meansresponsive to the photoelectric cell operating th means for altering thecutting advance, the support y means for holding and rotating the workpiece. that an oversized work piece intercepts some of the rays from thelight source and at a particular size ofthe work piece the photoelectriccell is energized.

2. In apparatus as claimed in claim l, the comv bination with the partsand features therein specifled of adjustment means to move the supportto being so located with relation to the'l adapt the apparatus fordierent sizes of work?- additional photoelectric cell, constructed andoperating as delined in claim l. whereby to effect dual control of thecutting advance to change from a' coarse grinding operation to a negrinding operation when one photoelectric cell is actuated and to causecessation of grinding when the other photoelectric cell is actuated.

4. In apparatus as claimed in claim l, the

combination with the parts and features therein energized.

RAYMOND A. COLE.

